How the world stopped sucking (for the middle class)

Here's a really interesting New York Times article about theories on why the human race was finally able to raise a substantial chunk of its population out of poverty around the time of the industrial revolution.

http://www.nytimes.com/2007/08/07/science/07indu.html?pagewanted=1
This explanation sounds good to me, but I'm always wary of just-so stories.

What do you all think?  Especially you amateur economists and raving libertarians.  :-)